JP2551863B2 - Mold for molding thermoplastic resin foam container and molding method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is for molding a thermoplastic foamed resin container using a thermoplastic foamed resin sheet to mold a food container such as a bowl or a tray having a thread tail. The present invention relates to a mold and a molding method using the mold.

<Prior Art and Problems to be Solved by the Invention> As a molding die for a thermoplastic foamed resin container, a thermoplastic foamed resin sheet is used to mold a food container having a thread tail at the bottom. -45113 gazette and Japanese Patent Publication 1-34135
The one as shown in Japanese Patent Publication was known. That is, in these molding dies, a movable yarn tail part is provided in a male mold or a female mold, and a heat-softened thermoplastic foamed resin sheet is arranged between the male mold and the female mold to make the male mold and the female mold. The container body is molded by pressure bonding to a mold, and then the yarn tail forming section is moved to form the yarn tail at the bottom of the container body.

In the molding die for such a foamed resin container, since the thread tail molding portion is movably provided in the male mold or the female mold, the structure of the mold becomes complicated, which causes a failure, and the molding efficiency is increased. There is a problem that not only the mold is lowered, but also the mold itself becomes expensive.

Furthermore, since a molding method using such a molding die requires two steps, a step of molding the container body and a step of molding the yarn tail, the molding cycle becomes long and the productivity is poor. was there. The present invention has been made to solve the above problems, and provides a molding die for a foamed resin container capable of molding a container body and a thread tail in one step, and a molding method using the same. It is intended to be provided.

<Means for Solving the Problems> A molding die for a thermoplastic foamed resin container of the present invention has a thickness of 0.05 to 2 mm for forming a tail of a yarn formed separately from the bottom of a mold surface forming a container body. And a groove for thread tail forming into which the thin plate is inserted are provided at the bottom of the mold surface for molding the container body, and an air intake hole is provided on the inner surface of the groove for vacuum forming. And female type.

Further, the molding method of the thermoplastic foamed resin container of the present invention,
A male die with a thin plate with a thickness of 0.05 to 2 mm, which is formed separately from the mold from the bottom of the mold surface for molding the container body, and which projects from the bottom, and a yarn tail for inserting the thin plate. The heat-softened thermoplastic foamed resin sheet is placed between the groove of and the female mold for vacuum forming provided at the bottom of the mold surface for molding the container body, and then the male mold is inserted through this thermoplastic foamed resin sheet. And the female mold are pressure-bonded to each other, and at the same time, the thermoplastic foamed resin sheet softened by heating is pushed into the groove of the female mold with the thin plate, and the thermoplastic foamed resin sheet is sucked from the intake hole provided in the inner surface of the groove of the female mold. Is closely attached to the inner surface of the groove to integrally form the container body and the thread tail.

<Operation> According to the molding die of the present invention, the male die is provided with a thin plate for forming the tail end having a thickness of 0.05 to 2 mm, and the female die is provided with a groove for the tail end molding into which the thin plate is inserted. Since it is for vacuum forming with an air intake hole provided on the inner surface of the groove, when the thermoplastic foamed resin sheet that has been softened by heating is placed between them and crimped, the thermoplastic foamed resin sheet is thinned inside the groove. Be pushed into. The thermoplastic foamed resin sheet inside the groove sucks the inside of the groove through the intake hole, and thereby adheres to the inner surface of the groove to form a yarn tail. At this time, unlike normal match mold molding, the thread tail is molded using a thin plate, so
The thread tail can be molded at the same time when the container body is molded, and there is no need to mold the thread tail by providing a movable part in the male or female mold.
No complicated mold processing is required, the male and female structures are simple, and the process of operating the movable part is not required, and the molding process of the foamed resin container is simplified. Moreover, the formed thread tail is not thick and is preferable in appearance.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a mold for molding a foamed resin container according to an embodiment of the present invention.

In the figure, reference numeral 1 is a bowl-shaped male die, and a cylindrical thin plate 3 for forming the tail end is formed on the bottom of the male die 1 separately from the die.

On the other hand, a thread tail forming groove 4 into which the thin plate 3 is inserted is provided at a position corresponding to the thin plate 3 of the male mold 1 at the bottom of the mold surface for molding the container body of the female mold 2. .

The thin plate 3 is made of a filler gauge, and is sandwiched between the core 7 and the gauge pressing portion 8 and the gauge pressing portion 8 is fastened to the core 7 side with the bolt 10 so that the thin plate 3 is projected from the bottom of the male mold 1. It is assembled in the male mold 1 in the state.

The thin plate 3 has a thickness of 0.05 to 2 mm, preferably 0.05 to 1 mm, which is desirable for forming a thread tail having an appropriate thickness and forming a thread tail having an appropriate strength.

Further, the protruding length of the thin plate 3 is the thermoplastic foam between the tip of the thin plate 3 and the bottom portion 4a of the groove 4 in a state where the male mold 1 and the female mold 2 are fitted with each other through the thermoplastic foam resin sheet. To the extent that a gap approximately equal to the thickness of the resin sheet is formed, specifically,
The protruding length of the thin plate 3 is 2 to 10 mm, preferably 5 to 8 mm, and the thin plate 3 can be inserted to a position 0.1 to 1 mm away from the bottom of the groove 4, preferably 0.5 mm away from the bottom of the groove 4. Set the protrusion length of 3.

The thin plate 3 has a ring shape, and the size of the thread tail formed at the bottom of the foamed resin container can be freely set by arbitrarily setting the diameter.

As shown in an enlarged view in FIG. 2, the gauge pressing portion 8 has a peripheral wall having a tapered shape in which the diameter is gradually reduced as it approaches the upper end, and the diameter is gradually reduced as it approaches the upper end corresponding to the tapered surface. If the structure is such that the taper ring 18 is interposed between the thin plate 3 and the gauge pressing portion 8 and the thin plate 3 is held by the core 7 and the gauge pressing portion 8, the gauge pressing portion 8 is tightened by tightening the bolt 10. Moves in the direction of the arrow F in the figure, tightens the taper ring 18, and strengthens the thin plate 3 more firmly.
Can be fixed to the male mold 1.

The taper ring 18 may have a slit in the axial direction or may be divided into a plurality of pieces in the axial direction.

As shown in FIG. 1, the female mold 2 includes a base 20 and a base 20.
20 is fixed by a bolt 11 on the top of the cavity 2a having a circular hole portion 21 at the bottom and a diameter smaller than the diameter of the hole portion 21 of the cavity 2a. ′
The cavity core 2b is fixed to the base 20, and the groove 4 is formed by the peripheral wall of the cavity core 2b and the inner wall of the hole 21 of the cavity 2a.

An intake hole 9 (shown by a broken line) for sucking the inside of the groove 4 is provided at an appropriate portion of the groove 4 in the bottom portion 4a of the groove 4, and an exhaust passage 12 (shown by a broken line) is provided below the intake hole 9. ) Are installed in a row.

The groove 4 has a width substantially equal to the thickness obtained by adding the thickness of the thin plate 3 to the thickness when the thermoplastic foamed resin sheet is folded in two, and the male mold and the female mold are formed of the thermoplastic foamed resin sheet. In the state of being fitted with each other, a gap approximately equal to the thickness of the thermoplastic foam resin sheet is formed between the tip of the thin plate and the bottom 4a of the groove 4. More specifically, the thin plate 3 has a thickness of 0.05 to 2 mm,
Preferably 0.05 to 1 mm, protrusion length 2 to 10 mm, preferably 5 to 8 mm, width 3 to 7 mm, preferably 4 to 5 mm, depth
The thickness of 0.5 to 10.5 mm, preferably 3 to 8.5 mm is desirable for molding a thread tail having an appropriate thickness and forming a thread tail having an appropriate strength.

Examples of the thermoplastic foamed resin sheet arranged between the male mold 1 and the female mold 2 include vinyl chloride, polyacrylate,
Examples include foamed resin sheets of polycarbonate, polyethylene, polystyrene, polyamide, acetate, polypropylene and the like.

Next, a molding method for forming a foamed resin container using the male mold 1 and the female mold 2 having the above-described configurations will be described with reference to FIGS.

(1) With the male die 1 and the female die 2 heated to a predetermined temperature, a heat-softened thermoplastic foamed resin sheet a is placed between the two as shown in FIG.

(2) As shown in FIG. 4, the male die 1 is moved toward the female die 2 so that the thin plate 3 pushes the thermoplastic foamed resin sheet a into the groove 4 so that the bottom portion of the male die 1 is female. At the bottom of the mold 2, the thin plate 3 is pressure-bonded to the peripheral side surface in the groove 4, and the peripheral side surface of the male mold 1 is pressure-bonded to the inner side surface of the female mold 2 via the thermoplastic foamed resin sheet a, respectively. Thermoform a.

(3) As shown in FIG. 5, the thermoplastic foamed resin sheet is sucked in the groove 4 in the direction indicated by the arrow A by a vacuum pump (not shown) or the like through the suction hole and the exhaust passage 12 connected to the suction hole. The thermoplastic resin sheet a is molded by bringing a into close contact with the inner surface of the groove 4.

(4) After molding, as shown in FIG. 6, the male die 1 is separated from the female die 2, and the temperature of the female die 2 is lowered by, for example, a cooling device or the like to cool and solidify the thermoplastic foamed resin sheet a. Then, it is taken out from the female mold 2. In this way, a bowl-shaped molded product 6 having the thread tail 5 is obtained.

Next, the molding of the thread tail will be described in detail with reference to FIGS. 7 to 11.

As shown in FIG. 7, the flat-plate heat-softened thermoplastic foamed resin sheet a is attached to the surface of the thin plate 3 by moving the thin plate 3 in the direction indicated by the arrow F in FIG. In this state, push it into the groove 4.

In the state where the male die 1 and the female die 2 are pressure-bonded, the groove 4 is filled with the thermoplastic foam resin sheet a, but as shown in FIG. 9, a gap 4b is formed at the corner of the bottom of the groove 4. There are cases. Then, when air is sucked into the groove 4 in the direction of the arrow A in the figure through the air inlet 9, the thermoplastic foam resin sheet a is brought into close contact with the inner surface of the groove 4 as shown in FIG. 10, and the gap 4b is eliminated. Next, by moving the thin plate 3 and taking out the thermoplastic foam resin sheet a, the yarn tail 5 can be formed. As shown in FIG. 11, the thread tail thus formed has a shape that is along the lengthwise shape of the groove 4 and has a bottom 5a that is horizontal and stable.

In the molding die having the above-described configuration, the male die 1 is provided with the thin plate 3 having a thickness of 0.05 to 2 mm for projecting the tail end, and the female die 2 is the groove for the tail end molding into which the thin plate 3 is inserted. 4 is provided, and furthermore, the inner surface of the groove 4 is provided with an intake hole 9 for sucking the inside of the groove 4. Therefore, when a heat-softened thermoplastic foamed resin sheet is placed between the two and pressure-bonded, a thin plate is formed. Thus, the thermoplastic foam resin sheet is pushed into the groove. The thermoplastic foamed resin sheet inside the groove sucks the inside of the groove through the intake hole, and thereby adheres to the inner surface of the groove to form a yarn tail. At this time, unlike the normal match mold molding, since the yarn tail is formed using a thin plate, the yarn tail can be formed at the same time when the container body is formed, and it is not necessary to provide a movable part in the male mold or the female mold. No complicated die machining is required, and the structures of the male die 1 and the female die 2 are simplified. Therefore, the male mold 1 and the female mold 2 can be manufactured efficiently at low cost.

Moreover, a complicated process such as operating the movable part is not required, and the molding process of the foamed resin container is simplified. further,
This shortens the molding cycle of the foamed resin container.

In the above embodiment, the intake air in the groove 4 is at the bottom.
Although it is done through the two intake holes 9 provided in 4a,
As shown in the drawing, further intake holes 9 '... may be provided, or as shown in FIG. 13, the bottom portion 4a' of the groove 4 may be formed of a breathable porous material. Further, as shown in FIG. 14, intake holes 9 ″ may be formed on the circumferential side surface of the groove 4.

Further, in the above embodiment, the mold for molding the bowl-shaped foamed resin container and the molding method thereof are described, but this is not limited to the bowl shape, and various design changes are made without departing from the scope of the present invention. Can be applied.

For example, the shallow dish 15 having the thread tail 13 shown in the plan view and the sectional view in FIGS. 15 and 16, and FIGS.
It is possible to obtain various foamed resin containers such as the square tray 16 having the thread tail 14 shown in the plan view and the sectional view in the figure.

Further, in the above embodiment, the cylindrical thin plate 3 and the groove 4 corresponding thereto form the cylindrical thread tail 5 at the bottom of the foamed resin container, but the thin plate and the groove are not formed respectively. As long as they have continuous corresponding shapes, it is possible to form a leg piece projecting at an arbitrary position on the bottom of the foamed resin container in the same manner as in the above embodiment.

Further, in the above embodiment, the case where the male mold and the female mold are used in the press molding method has been described, but the vacuum molding method using the male mold or the female mold or the double-sided vacuum molding method can also be performed.

<Effects of the Invention> As described above, according to the molding die of the present invention, the male die is provided with a thin plate for forming the tail end which is formed separately from the die and has a thickness of 0.05 to 2 mm. Is for advance molding with a groove for thread tail molding in which the thin plate is inserted and an intake hole is provided on the inner surface of the groove, so a heat-softened thermoplastic foamed resin sheet is placed between the two. When pressed and pressed, the thermoplastic foamed resin sheet is pushed into the groove by the thin plate, and the thermoplastic foamed resin sheet inside the groove adheres to the inner surface of the groove by inhaling the inside of the groove through the air intake hole to form the groove shape. It is possible to form a stable shape thread tail. At this time, unlike the normal match molding, the thickness of 0.05
Since the thread tail is molded using a thin plate of ~ 2 mm, the thread tail can be molded at the same time as the container body is molded. There is no need, complicated mold processing is unnecessary, thin plates can be easily replaced, and the male and female structures are simple and inexpensive. Moreover, the molding method does not require a complicated process such as moving the movable part, and the molding process of the foamed resin container can be simplified and the molding cycle can be shortened.

[Brief description of drawings]

1 is a sectional view showing a molding die according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of the molding die, and FIGS. 3 to 6 are moldings of a foamed resin container according to the present invention. Sectional view for explaining the method, FIGS. 7 to 11 are enlarged cross-sectional views of the essential parts for explaining the molding method of the tail portion of the foamed resin container, and FIGS. 12 to 14 are the expanded resin container. Main part enlarged sectional view showing another example of the molding die, FIGS. 15 and 16 are plan views and sectional views showing another example of the foamed resin container according to the present invention, and FIGS. 17 and 18 are books. It is the top view and sectional view which show other examples of the foaming resin container in the invention. 1 ... Male type, 2 ... Female type, 3 ... Thin plate, 4 ... Groove, 5,13,14 ... Thread tail, 9 ... Intake hole

Claims (2)

(57) [Claims] 1. A male mold in which a thin plate having a thickness of 0.05 to 2 mm for projecting from the bottom of the mold surface forming the container body is formed separately from the mold, and a thread into which the thin plate is inserted. A thermoplastic foamed resin container characterized in that a bottom-forming groove is provided at the bottom of a mold surface for molding the container body, and a vacuum-forming female mold having an intake hole provided on the inner surface of the groove is provided. Mold for molding. 2. A male mold in which a thin plate having a thickness of 0.05 to 2 mm for thread tail formation, which is formed separately from the mold from the bottom of the mold surface for molding the container body, is projected on the bottom, and the thin plate is inserted. A heat-softened thermoplastic foamed resin sheet is placed between a vacuum molding female die provided with a thread tailing groove at the bottom of the mold surface for molding the container body, and this thermoplastic foamed resin sheet is then placed. The male mold and the female mold are pressure-bonded through each other, and at the same time, the thermoplastic foamed resin sheet that has been softened by heating is pushed into the groove of the female mold by the thin plate, and the air is sucked from the intake hole provided on the inner surface of the groove of the female mold. A method for molding a thermoplastic foamed resin container, characterized in that a container body and a thread tail are integrally molded by closely adhering a thermoplastic foamed resin sheet to the inner surface of the groove.